Drawing instrument



July 24, 1951 A. M KILLOP DRAWING INSTRUMENT Filed April 19, 1948 INVENTOR. ANDREW Mc KlLLOP FLG. 5.

ATTORNEYS Patented July 24, 1951 UNITED STATES .lPATENT OFFICE "DRAWING msrnu unu'r Andrew McKillop, Detroit, inch. Application np c, 1948, Serial No. 21.990

4 Claims.

' The invention relates to drawing instruments and refers more particularly to instruments for use in drawing straight or curved lines uniformly spaced from or parallel to each other.

The invention has for one of its objects to provide an improved drawing instrument having openings therethrough designed for use with a chisel pointed pencil and formed so that the instrument may be moved by the pencil without affecting the spacing of the lines.

The invention has for another object to provide an improved drawing instrument which may be moved along the convex side or concave side of a draftsmans curve instrument to secure accurately spaced lines.

With these and other objects in view the invention resides in the novel features of construction as more fully hereinafter set forth.

In the drawings:

Figure 1 is a plan View of a drawing instrument embodying the invention;

Figure 2 is an edge elevation thereof;

Figures 3 and 4 are views illustrating the use of the drawing instrument;

Figure 5 is a view similar to Figure 1 showing a modified construction of drawing instrument; and

Figure 6 is an edge elevation of Figure 5.

As illustrated in Figures 1, 2, 3 and 4, the drawing instrument is a circular disk I having the circular periphery 2, the concentric opening 3 therethrough, and also the openings 4 therethrough. The disk may be formed of suitable material, such as a plastic or steel, the plastic being preferable. Each opening 4 is generally rectangular, it being formed with the radially spaced inner and outer arcuate sides 5 concentric with the periphery of the disk and the straight sides 6 extending generally radially of the disk and transversely of the sides 5 and forming therewith radially outer angle corners. More particularly, the straight sides 6 are inclined to the radii 6 passing through these sides, their extensions as shown by the dash lines (:3 in Figure 1 intersecting and being tangent to the circle 6 concentric with the center or axis of the disk and passing through points on the circle laterally ofiset in opposite directions so that the straight sides form acute angles with the adjacent end portions of the radially outer sides 5. The radially outer arcuate sides of the successive openings are spaced progressively increasing distances from the periphery of the disk and more particularly the peripheral portions adjacent to and radially outwardly of the openings whereby the openings are spirally arranged. The disk is provided with suitable indicia 1 radially inwardly of the openings for designating the distances from the radially outer arcuate sides of the openings to the adjacent portions of the periphery of the disk to facilitate securing the desired spacing between lines.

The above construction of drawing instrument with its angle corners provides for the using of a chisel pointed pencil which is commonly used by draftsmen and which maintains its accuracy for a longer time than an ordinary conically pointed pencil. Also the construction is. such that the drawing instrument may be used at either the outer convex or inner concave sides of a draftsmans curve instrument 8 or curve instrument 9 of Figures 3 and 4 respectively, and may be advanced in either direction along the sides of the curve instruments or along the straight side of an instrument by the pencil engaging one of the radially outer angle corners of an opening, these corners being acute to assist in maintaining the pencil against the radially outer side of the opening. Furthermore, the construction is such that the pencil may move over the radially outer side of an opening of the drawing instrument without destroying the desired accuracy of the spacing of the lines.

Figures 5 and 6 illustrate a modified construction of drawing instrument in which the disk 10 is polygonal, it having as shown a hexagonal periphery. In this construction, the openings 11, designed for use with a chisel pointed pencil, are rectilinear and arranged in radial series with and at diiTerent distances from the rectilinear portions of the periphery, the radially outer sides of the openings and also their radially inner sides being parallel to the adjacent straight portions of the periphery. This construction of drawing instrument is adapted particularly for use in being moved along the straight or convex sides of a draftsmans instrument.

What I claim is:

1. A drawing instrument comprising a circular disk having openings therethrough, each formed with an arcuate side concentric with the adjacent portion of the periphery of the disk and with other sides extending transversely of and toward the periphery of said disk and connecting into said concentric side and forming acute angle corners therewith, said concentric sides of said openings being spaced diiferent distances from the periphery of said disk.

2. A drawing instrument comprising a disk having generally rectangular openings there-i 3 through, each formed with sides spaced throughout their lengths the same distances from the adjacent portion of the periphery of said disk and with other sides extending transversely of and connecting into said first mentioned sides and forming acute angle corners with the sides nearest the periphery of said disk, said openings being arranged in radial series at different distances from the periphery of said diski 3. A drawing instrument comprising a sirenlar disk having generally rectangular openings therethrough, each opening being formed with a flhel iollowing references are of record in the radially inner and outer arcuate sides .cgncgntriiic' with the adjacent portion of the periphery e disk and with straight sides extending .transr' 5 intosasaid t,,mgn:

versely of and connecting 5 tions of the periphery of the disk and with tioned sides, said straight sides" lii'rig' iiiclified to the radii passing therethrough so that theirvx-J;

tensions intersect and are tangent to a circle concent ic wi the a i oirt e isitisksan pas wrench points n theci el latera lr ff ti n gnposi eed motion v whereby said t a g t-si es iqrm cu an l cor e wi h sai rad a lyi oute 's des su Q ssiv open n ha ingt eir a ian-rim; amid s spaced, progressively increasing distances 1 from the periphery of Said disk. 7

4. A drawing instrument comprising;

"Nuirlber Name Date $23,078 Holz July 18, 1899 1,154,673 Van Ness Sept. 28, 1915 is 9 43 m 2 492 ne 1 352,405 Polowe June 27, 1944 25 OTHER- REFERENCES straight sides connecting said arcuate sides and extending generally radially of said disk, said arcuate outer sides being spaced difierent disranaes fiom thep'eripherypi said disk;

DREW MCKILLOP.

REFERENCES CITED vfile of patent: STATES PATENTS 

